2-Amino-5-methyl­pyridinium 4-methyl­benzoate

The 4-methyl­benzoate anion of the title salt, C₆H₉N₂⁺·C₈H₇O₂⁻, is nearly planar, with a dihedral angle of 6.26 (10)° between the benzene ring and the carboxyl­ate group. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms of the anion via a pair of N—H...O hydrogen bonds with an R₂²(8) ring motif, forming an approximately planar ion pair with a dihedral angle of 9.63 (4)° between the pyridinium and benzene rings. The ion pairs are further connected via N—H...O and weak C—H...O hydrogen bonds, forming a two-dimensional network parallel to the bc plane.

2-Amino-5-methyl­pyridinium 2-hy­droxy-5-chloro­benzoate

In the 5-chloro­salicylate anion of the title salt, C₆H₉N₂⁺·C₇H₄ClO₃⁻, an intra­molecular O—H...O hydrogen bond with an S(6) graph-set motif is observed and the dihedral angle between the benzene ring and the –CO₂ group is 1.6 (6)°. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms via a pair of N—H...O hydrogen bonds, forming an R₂²(8) ring motif. The crystal structure also features N—H...O and weak C—H...O inter­actions, resulting in a layer parallel to (10-1).

2-Amino-5-methyl­pyridinium 4-chloro­benzoate

The 4-chloro­benzoate anion of the title salt, C₆H₉N₂⁺·C₇H₄ClO₂⁻, is nearly planar with a dihedral angle of 5.14 (16)° between the benzene ring and the carboxyl­ate group. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms of the anion via a pair of N—H...O hydrogen bonds with an R₂²(8) ring motif. The ion pairs are further connected via N—H...O and weak C—H...O hydrogen bonds, forming a two-dimensional network parallel to the bc plane. The crystal structure also features a π–π stacking inter­action between the pyridinium and benzene rings with a centroid–centroid distance of 3.7948 (9) Å.

2-Amino-5-methyl­pyridinium 3-hy­droxy­pyridine-2-carboxyl­ate

In the 3-hy­droxy­picolinate anion of the title salt, C₆H₉N₂⁺·C₆H₄NO₃⁻, an intra­molecular O—H...O hydrogen bond with an S(6) graph-set motif is formed, so that the anion is essentially planar, with a dihedral angle of 9.55 (9)° between the pyridine ring and the carboxyl­ate group. In the crystal, the cations and anions are linked via N—H...O hydrogen bonds, forming a centrosymmetric 2 + 2 aggregate with R₂²(8) and R₄²(8) ring motifs. The crystal structure also features N—H...N and weak C—H...π inter­actions.